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Is Your Project Timeline Based on a Sample of 1? Do this INSTEAD...

Letโ€™s face it, as human beings weโ€™re terrible at estimating how long a project will take to complete (even Elon Musk has been off by YEARS in his predictions for SpaceX!)


๐—ช๐—›๐—ฌ? Two reasons:


โŒ Weโ€™re simply too optimistic and assume everything will go well.


โŒ Calculating a single completion time does not FORCE us to consider alternate scenarios.


Once THE DATE been communicated, everyone tends to remember THE DATE โ€“ and NOT the underlying ASSUMPTIONS behind it, no matter how carefully they're stated.


๐—” ๐—ฆ๐—ผ๐—น๐˜‚๐˜๐—ถ๐—ผ๐—ป?


A variation of PERT analysis; PERT stands for ๐˜—๐˜ณ๐˜ฐ๐˜จ๐˜ณ๐˜ข๐˜ฎ ๐˜Œ๐˜ท๐˜ข๐˜ญ๐˜ถ๐˜ข๐˜ต๐˜ช๐˜ฐ๐˜ฏ ๐˜ข๐˜ฏ๐˜ฅ ๐˜™๐˜ฆ๐˜ท๐˜ช๐˜ฆ๐˜ธ ๐˜›๐˜ฆ๐˜ค๐˜ฉ๐˜ฏ๐˜ช๐˜ฒ๐˜ถ๐˜ฆ. Even though it was first used by the US Navy in the 50โ€™s for the development of the Polaris submarine-launched nuclear missile, itโ€™s not rocket science:


In PERT, for each project task we calculate 3 durations:


๐Ÿ‘‰ Optimistic (O): min. time to accomplish (best-case scenario)


๐Ÿ‘‰ Pessimistic (P): max. time to accomplish (worse-case scenario)


๐Ÿ‘‰ Most Likely (M): best current estimate to accomplish


A project plan for each of the three scenarios can then be developed and analyzed in MS Project, Excel, etc. to determine a RANGE of project durations and completion dates.


๐๐„๐๐„๐…๐ˆ๐“๐’ ๐จ๐Ÿ ๐๐„๐‘๐“ ๐ข๐ง๐œ๐ฅ๐ฎ๐๐ž:


โœ… A series of realistic scenarios for our project based on what can go right AND what can go WRONG!


โœ… NOT being tied down to a single (uncertain) date, since the output is a RANGE of completion times.


โœ… An estimate of the VARIABILITY in our project timeline.


Even IF a completion date cannot be moved (say due to an audit or regulatory deadline), the three estimates can be used to calculate project duration with:


๐Ÿ”น Additional resources (Optimistic)


๐Ÿ”น Current resources (Most Likely)


๐Ÿ”น Less resources (Pessimistic)


Which can help us figure out whether weโ€™ll need additional people, machines, material, etc. to meet our deadline.


We would NOT make an important decision based on a sample of n = 1 if we could avoid it, so why base your project timeline on a single estimate?

Give PERT analysis a try when scheduling your next project.



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